1/26/2006 FCST: North TX & Southern OK

Heads Up! Just glanced forward at the GFS which shows an approaching negatively tilted mid level trough passing through the target area on this Thursday. Right now the biggest negative I see is the apparent quick approach of the mid level system that may make it difficult for good surface cyclogenesis and definition of boundaries. This will then be further limited (according to current model run) by lack of enough time for good moisture advection with only dewpoints of 45 making it up into southern OK. However I am hoping that it may slow a bit more and give a bit more time. Plus the NAM once it starts picking up this feature may be a bit more positive on moisture return.

Additionally, somewhat difficult to determine a sfc boundary near this area as the larger front will be further north toward KS/NE, but I'm thinking that the return flow from the gulf will help to reinforce / create a more localized warm frontal boundary that will translate through the Red River area during the day. Additionally there is the approach of the trough directly to the west of DFW and apparent dryline.

The biggest positives I see are some very intense mid to upper jets and strong supporting 850mb jets and reasonable sfc flow. Already mentioned the incoming neg tilt with a very compact 500mb pva through north Tx transitioning through eastern OK up until 0Z. The mid and upper level lift should cause extensive breakout of precipitation both in OK, and TX. There is also good vertical directional shear with 850mb being somewhat weak, but 700mb very compact. 500mb shows a bit of mid level divergence over / near the DFW region in later afternoon and there is also a 300 mb jet overhead with possible left exit region possibilities as I see it.

So to repeat the biggest prob is moisture and sfc boundary / low - quality formation. If we can get the slowing of the mid level low, intensyfying of the sfc low and moisture return expect supercells with tornadoes. If not and it ends up as the GFS says now expect some widespread rain, but still some possibility of scattered supercells near the DFW/North Texas/Red River Region with possibly a few tornadoes especially further in the southern region in better moisture, along boundaries and near encroaching dryline bulge.

Disclaimer: All that said, but assuming the GFS doesn't lie and totally change as Thur approaches - LOL!
 
Once again wanted to re-iterate my Thursday scenario is based on enough moisture return. IMO everything else is there. True, the model doesn't show much return and truth is it may not be enough. It does show near 50 dewpoints close to the DFW region. That normally should be enough for some action unless it is too thin a layer. There are some strong jets forecast by the GFS on the 12z run today. If those materialize I still think there could be severe near that region. If not, well then just consider it my January chase 'wish cast'.

Guess you're all welcome to comment if you think I'm crazy. :lol:
 
Ensembles still showing quite a bit of spread on this trough ejecting through the Central CONUS in the Friday timeframe...and the measure of predictability is still rather low so I wouldn't bank on anything yet. That being said...there does appear to be general consensus that a trough will come through the area in some form.

The tricky thing about this low is that it will become cutoff and stall over the Northern Baja or portion of the Pacific Ocean just adjacent and as a result there probably won't be very good data coverage on it until the 12/18Z cycles on Wednesday.

We shall see...but not expecting anything yet. Could POTENTIALLY see something into the weekend too. Check out the 12Z ECMWF from today. Another shortwave barreling through...but with a deeper low.

...Alex Lamers...
 
Ensembles still showing quite a bit of spread on this trough ejecting through the Central CONUS in the Friday timeframe...and the measure of predictability is still rather low so I wouldn't bank on anything yet.

Yeah I should probably check the ensembles and not just GFS. I usually am reluctant to make much of a forecast off the GFS anyway. I've been burned on it a number of times in the past. It just isn't that accurate out past 3 or 4 days. That said, I guess I just got excited because of the area of vorticity and upper jets passing over the Red River area. The moisture issue is a big one since the Gulf won't be 'open for business' very long before this mid level trough gets in the area. Instability may be limited. Odds are future model runs will be more negative rather than more positive, but I thought I'd mention it anyway in case others hadn't seen it. If it actually does slow and somehow pull more moisture / instability then I think it could be an event to watch; otherwise it may be tough. Guess we'll see how it goes. Given what the GFS showed yesterday 12z though if that unfolded exactly as shown I do think there will be at a minimum thunderstoms up toward DFW and the Red River area - with the jets as forecast possibly even supercells, but then again it's still based on moisture and instability and if that 45 to 50 dewpoint layer is thin and daytime temps don't rebound then just widespread rain. I haven't checked the latest GFS - should be interesting to see how it changes. The run before the one I used had the area of vorticity coming in on Friday so the 12z run already had sped it up by 12hours. That's a lot of variability.


We shall see...but not expecting anything yet. Could POTENTIALLY see something into the weekend too. Check out the 12Z ECMWF from today. Another shortwave barreling through...but with a deeper low.
...Alex Lamers...

Yeah I saw that one too - just didn't mention it. Thanks for the thoughts Alex. Probably I'm hoping it doesn't materialize for Thurs anyway. I have too much I need to be doing rather than being distracted by chasing in January. :lol:
 
Just glanced at the NAM as the event is on it's horizon now, and it looks bad. Moisture return is meager with 50's dewpoints showing on Tx coast by 0Z and area of 500mb vorticity is shown displaced substantially further north than the earlier GFS runs were showing. The NAM also cuts out most / all of the precip chances in north Tx / Ok. So, this may be a non-event as far as this area is concerned.
 
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